Causes

Whipple disease is caused by a type of bacterium called Tropheryma whipplei. The bacteria affect the mucosal lining of your small intestine first, forming small sores (lesions) within the wall of the intestine. The bacteria also damage the fine, hairlike projections (villi) that line the small intestine.

Not much is known about the bacteria. Although they seem readily present in the environment, scientists don't know where they come from or how they're spread to humans. Not everyone who carries the bacteria develops the disease. Some researchers believe that people with the disease may have a genetic defect in their immune system response that makes them more likely to become sick when exposed to the bacteria.

Whipple disease is extremely uncommon, affecting fewer than 1 in 1 million people.